What are the most coomon reasons for your projects falling behind schedule?

I am working on a resource that lists the most common reasons projects fall behind schedule. So far, I have narrowed it down to 7 - Shadow work, Biased estimations, Scope creep, resource overutilization, Meeting hell, Noisy feedback, Poor organization. Would you add anything else to this list? Here is the post - https://teamhood.com/productivity/behind-schedule/